BMC BMC Bulldozer Assembly Power Take-off Torque Converter Universal Joint Transmission Unit Main Drive Steering Clutch Steering Brake Final Drive Track Equipment Control System Working Equipment Cabin Floor & Fender Track Frame
BMC BMC Engine Torque Converter Universal Joint Gear Box Main Drive Steering Clutch Final Drive Track System Power Train
BMC BMC Function: PTO powerEquipment: Work system pump Transmission pump Steering Pump Power Take-off
BMC BMC Type: 3-element 1 stage 1 phase Assembly: Pump, Turbine and Stator There are many vanes on these components for using oil to transfer power Torque Converter Assembly
BMC BMC These 3 components combined with oil, give us as smooth power transmission. Safety valve: fitted to oil input, ensures the input oil pressure is no more than 0.87MPa. Relief Valve: fitted on oil output, ensures the oil pressure inside the torque converter is maintained below 0.45MPa.
BMC Oil Flow: Pump Turbine Stator pump There is 2 mm clearance between pump and Turbine, and transfers power by Oil. There is no mechanical impact, they protect each other Assist hydraulic system: to resist loss of oil; to maintain the normal oil temperature. Principles of Torque Converter
BMC BMC When the load increases, the dozer ground speed is reduced, causing turbine speed to slow down. But at this time the energy from the pump transfer to torque converter is not reduced. This energy is still transferring to the stator through the slowing turbine. Then the energy to stator from turbine, results in the turbine gaining torque, then the turbine output torque is increasing. Operation of Torque Converter
BMC BMC 1.Change torque automatically 2.Absorb vibration, prolong working life 3.Good power transmission capability, driving at slow speed 4.Simple operation 5. Start smoothly, eliminates any shocks in power train 6.Easy maintenance Torque Converter Operation
BMC BMC Normally, SD22 Torque Converter Temperature of output oil is o C. For a short time, a higher temperature of o C is allowed, but long term high temperature shows there is something wrong, for the following reasons: 1.Shortage of Oil Torque converter, transmission, main drive, steering and final drive will take 30% of engine rated power. This power will transfer to heat energy, and increase the oil temperature. Therefore it requires enough oil to absorb this heat. If the oil quantity is not sufficient, the oil temperature will be too high. High Torque Converter Oil Temperature
BMC BMC 2.Oil Pressure of input and output are incorrect If torque converter input oil pressure is not correct (Standard: 0.87MPa) or the oil is dirty, the piston of valve will stay at relief position, so the oil pressure to the torque converter is low. This leads to a loss of efficiency and excessive oil temperature. If torque converter output oil pressure is not correct (Standard: 0.45MPa) or the oil supply is blocked, return oil temperature will be too high. The flow of oil to oil cooler is reduced, and the oil temperature too high
BMC BMC 3. Incorrect Operation Excessive use of low engine speed for extended time, torque converter will work at low efficiency. Torque converter will lose power, and transfer heat energy leading to high oil temperature.
BMC BMC The types of Transmission Case: Base Operation type: 1.Manual Gearshift 2.Hydraulic booster 3.Powershift Base Transmission type: 1.mechanical type; 2.Planetary Gear Planetary type powershift transmission case type: Planetary Gear, Multi-disc clutch, Hydraulic control, forced lubrication. Function: 1.Enable forward and reverse 2.Select different gear ratio 3.Matched with the torque converter, enables a wide range of power output and ground speed Power Transmission Case
BMC BMC The system consists of: A: Sun Gear B: Planetary Gears C: Ring Gear D: Carrier The planetary gears are installed on the carrier being in constant mesh with the sun gear and the ring gear Planetary Gear System A B C D
BMC BMC Planetary Gear system
BMC BMC Principle of Planetary Gear system A: Sun Gear B: Planetary Gear C: Ring Gear D: Carrier If the carrier is fixed, the torque is transmitted from sun gear to planetary gear, and is transmitted from planetary gear to ring gear to make the ring gear rotate. Rotation direction of ring gear is opposite from sun gear.
BMC BMC A: Sun Gear B: Planetary Gear C: Ring Gear D: Carrier If the ring gear is fixed, the torque is transmitted from sun gear to planetary gear. The planetary gear rotates by itself, at the same time rotates around sun gear. Rotation direction of the planetary gear shaft is opposite from sun gear. It is a slowdown outfit that power input from sun gear, output from carrier Principle of Planetary Gear system
BMC BMC The above principles are structure principle of No.1,3,4 planetary gear system. The sun gear is active in No.1 Planetary Gear system The carrier is active in No.3 & 4 Planetary Gear system
BMC BMC This is structure and principle of No.2 planetary gear system. The rotate direction is contrary with No.1 planetary gear system.
BMC BMC SD22 powershift transmission system Consists of 4 planetary gear systems with 4 clutches, and 1 locking clutch (no planetary gear system) and housing, input shaft, end gear and output bevel gear. No.1 clutch is for Forward Gear No.2 clutch is for Reverse Gear No.3 clutch is for 3rd Gear Shift No.4 clutch is for 2nd Gear Shift No.5 lock clutch is for 1st Gear Shift
BMC The 4 planetary gear system clutchs washers and disc are the same, but the disc quantity is different. Its design is based on transmission torque. SD22 powershift transmission system The No. of Clutch Washer Qty Disc Qty No.134 No.223 No.312 No.412 No.523
BMC BMC No.1- 4 planetary gear systems structure are same, clutches washer and disc are same, but the disc quantity and piston is different.
BMC BMC Method of fixing of each planetary gear is as this figure, it is actuated by the clutch. Engagement Engagement of clutch is actuated by oil pressure from control valve pushing piston 3.
BMC BMC Disengagement Disengagement of clutch is actuated by return spring 33 which pushes piston 3 to original position after oil pressure is cut off. The function of disc spring 42 is to improve operating speed of piston 3 and improve release the discs.
BMC BMC This figure is a drawing of No.5 locking clutch. When the clutch disengages, oil in the cylinder body 16 by the action of centrifugal force. Disks cant disengage quickly, only by disk spring 29. This can make the clutch half disengage. This will cause difficulty for next gearshift. In order to eliminate this problem, the ball check valve 17 is incorporated in the piston after the rotary clutch.
BMC BMC No.5 Clutch is a lock clutch. When this clutch engages, pressure oil from controlling valve enters into oil cavity and pushes piston 26, at the same time, the oil pushes check valve ball 17 to plug the hole of valve. The clutch is engaged quickly.
BMC BMC No.5 Clutch is a lock clutch. When the pressure oil from controlling valve is cut off, by the action of centrifugal force, ball 17 can move to the direction of arrow in this figure. At this time, the hole of valve cage is opened and the oil is drained off.
BMC BMC Forward 1 st Speed
BMC BMC Forward 2nd Speed
BMC BMC Forward 3rd Speed
BMC BMC Transmission Lubrication and Cooling: Its a forced lubrication system, from above and below, two ways divided through a valve. Transmission Case lubrication pressure is 0.124Mpa. Upper way lubricates the second half bearing and cools the second half discs; lower way lubricates the first half bearing and cools first half discs.
BMC BMC Main Drive (SD22) Assembly:Assembly: Bevel gears Horizontal Shaft Bearings Sprocket Hub Functions:Functions: Power train gear reduction to increase the final drive torque
BMC BMC Function:Function: To disengage the shaft drive and control steering Type:Type: Wet, multi-disc, spring loaded, hydraulic separated, normally engaged. Spring forceSpring force F=3.2 tons Steering Clutch
BMC BMC Steering Clutch Operation
BMC BMC Steering Brake Function:Function: The brake on the outside of steering clutchs outside drum, reduced the rpm of the final drive on that side. Type:Type: Wet band, hydraulic boosted control
BMC BMC Linkage through valves Steering Brake Control
BMC BMC There are 3 associated components, Main drive, Steering Clutch and Steering Brake. They are lubricated and cooled by the oil in steering case. The oil level can be checked with oil dipstick Steering case has a breather to balance inside and outside pressures. Steering Case Lubrication and Breather
BMC BMC Final Drive: One Set Final Drive on each side. 2 stage spur gears reduction. Floating Seal and O-ring to contain oil, then connected outside with breather. Assembling Sprocket hub and gear requires 60 tons force with special tools. Final Drive
BMC BMC Assembly:Assembly: Track Frames Track Rollers Carrier Rollers Recoil system Track Shoes Equalizer Track System --- Walking Gear
BMC BMC Function:Function: 1. Maintain track tension 2 absorb the vibration of idler Note:Note: the fixed pressure is tons, it requires special fitting tools Recoil system for Track
BMC BMC use a ruler placed on the track grousers between carrier roller and idler, the measure distance is C C=20- 30mm SD32 track has more wide, the distance is bigger between carrier roller and idler, the measured distance is C=30-40mm Measurement of Track Tension IdlerCarrier roller
BMC BMC Function:Function: Gives guidance for track chain and maintains track tension LubricationLubrication There are lub oil in the cage that is sealed by floating seal, between idler and support housing. The oil capacity is 70%. Idler
BMC BMC If the clearance is over limit, the idler will swing, and track links off centre and will wear the sprocket. If Clearance in one side A 4mm, it must be adjusted into A=0.5-1mm If Clearance of up and down (B+C)5mm it must be adjusted into (B+C)=2mm To Adjust Idler Clearance
BMC BMC First it carries dozer weight, secondly it prevent track chain moving off centre of track frame Bushing and float seal is similar to idler Track Roller
BMC BMC Supports all of the dozer weight, and determines the ground pressure Four high strength bolts fix track shoe onto track link, bolt torque: SD16:70kg.m SD22:76kg.m SD32:100kg.m Track Shoe Assembly
BMC BMC Track supports 30 tons bulldozer weight, and if the working conditions are bad, it will wear more quickly, so use and maintain it correctly. 1.Often check the tension of track shoe. use a ruler put the track grousers between carrier roller and idler, the measure is C C=20-30mm; SD32 track is more weight, the distance is more large between carrier roller and idler, the measure is C=30- 40mm When the work is hard, the track shoe assy will need to be adjust tighter; if the work is moderate, the track shoe assy tension can be adjusted back. Use and Maintenance of Track Shoe
BMC BMC 2. The sprocket segments need be replaced when the sprocket segments wear under the limit. 3. Dont drive dozer hard and avoid track damage and excessive wear. 4. If there is excessive track play and noise, you must stop and check tracks and machine. 5. When the dozer across the railway line, you must drive it across the railway at right angle, and dont change speed, dont stop and reverse, avoid track shoes locking in railway line. 7. After working, you must check tracks, and if there is something wrong. If there is something wrong, must repair or replace. Use and Maintenance of Track Shoe
BMC BMC End of this Training Module Thanks Your Cooperation !!! End of this Training Module Thanks Your Cooperation !!!